From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3492C678D4 for ; Tue, 7 Mar 2023 17:49:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232212AbjCGRt6 (ORCPT ); Tue, 7 Mar 2023 12:49:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232233AbjCGRt2 (ORCPT ); Tue, 7 Mar 2023 12:49:28 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5F6E9CBFB for ; Tue, 7 Mar 2023 09:44:18 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 79923B81850 for ; Tue, 7 Mar 2023 17:44:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5FB1C433EF; Tue, 7 Mar 2023 17:44:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678211057; bh=x8QQC8Sso74aHc/fshn/Nnjs36aQLerzYq2RGzsexfQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Wq9/nmCngFvuKRgIz2y2j/q5MaU9fCd25qe4UkZPDeO5XURcmYv5lmaHYmcny9PH+ 9PwS2Y9rnYCh25FqWh0AgVdYYs08Ue3wzjp/Sne6VFPQBl4bcPuQtoSzEJBhEPW4A3 FVGyRquu8M/vCMNw4PvMJJzIu4cO79bZaTNJVAzo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Paulo Alcantara (SUSE)" , Steve French , Sasha Levin Subject: [PATCH 6.2 0740/1001] cifs: prevent data race in smb2_reconnect() Date: Tue, 7 Mar 2023 17:58:32 +0100 Message-Id: <20230307170053.847257904@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307170022.094103862@linuxfoundation.org> References: <20230307170022.094103862@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paulo Alcantara [ Upstream commit 3c0070f54b3128de498c2dd9934a21f0dd867111 ] Make sure to get an up-to-date TCP_Server_Info::nr_targets value prior to waiting the server to be reconnected in smb2_reconnect(). It is set in cifs_tcp_ses_needs_reconnect() and protected by TCP_Server_Info::srv_lock. Signed-off-by: Paulo Alcantara (SUSE) Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/smb2pdu.c | 119 +++++++++++++++++++++++++--------------------- 1 file changed, 64 insertions(+), 55 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 3b93680a319e4..5a063af8a094e 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -139,6 +139,66 @@ smb2_hdr_assemble(struct smb2_hdr *shdr, __le16 smb2_cmd, return; } +static int wait_for_server_reconnect(struct TCP_Server_Info *server, + __le16 smb2_command, bool retry) +{ + int timeout = 10; + int rc; + + spin_lock(&server->srv_lock); + if (server->tcpStatus != CifsNeedReconnect) { + spin_unlock(&server->srv_lock); + return 0; + } + timeout *= server->nr_targets; + spin_unlock(&server->srv_lock); + + /* + * Return to caller for TREE_DISCONNECT and LOGOFF and CLOSE + * here since they are implicitly done when session drops. + */ + switch (smb2_command) { + /* + * BB Should we keep oplock break and add flush to exceptions? + */ + case SMB2_TREE_DISCONNECT: + case SMB2_CANCEL: + case SMB2_CLOSE: + case SMB2_OPLOCK_BREAK: + return -EAGAIN; + } + + /* + * Give demultiplex thread up to 10 seconds to each target available for + * reconnect -- should be greater than cifs socket timeout which is 7 + * seconds. + * + * On "soft" mounts we wait once. Hard mounts keep retrying until + * process is killed or server comes back on-line. + */ + do { + rc = wait_event_interruptible_timeout(server->response_q, + (server->tcpStatus != CifsNeedReconnect), + timeout * HZ); + if (rc < 0) { + cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n", + __func__); + return -ERESTARTSYS; + } + + /* are we still trying to reconnect? */ + spin_lock(&server->srv_lock); + if (server->tcpStatus != CifsNeedReconnect) { + spin_unlock(&server->srv_lock); + return 0; + } + spin_unlock(&server->srv_lock); + } while (retry); + + cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__); + return -EHOSTDOWN; +} + static int smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, struct TCP_Server_Info *server) @@ -146,7 +206,6 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, int rc = 0; struct nls_table *nls_codepage; struct cifs_ses *ses; - int retries; /* * SMB2s NegProt, SessSetup, Logoff do not have tcon yet so @@ -184,61 +243,11 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, (!tcon->ses->server) || !server) return -EIO; - ses = tcon->ses; - retries = server->nr_targets; - - /* - * Give demultiplex thread up to 10 seconds to each target available for - * reconnect -- should be greater than cifs socket timeout which is 7 - * seconds. - */ - while (server->tcpStatus == CifsNeedReconnect) { - /* - * Return to caller for TREE_DISCONNECT and LOGOFF and CLOSE - * here since they are implicitly done when session drops. - */ - switch (smb2_command) { - /* - * BB Should we keep oplock break and add flush to exceptions? - */ - case SMB2_TREE_DISCONNECT: - case SMB2_CANCEL: - case SMB2_CLOSE: - case SMB2_OPLOCK_BREAK: - return -EAGAIN; - } - - rc = wait_event_interruptible_timeout(server->response_q, - (server->tcpStatus != CifsNeedReconnect), - 10 * HZ); - if (rc < 0) { - cifs_dbg(FYI, "%s: aborting reconnect due to a received signal by the process\n", - __func__); - return -ERESTARTSYS; - } - - /* are we still trying to reconnect? */ - spin_lock(&server->srv_lock); - if (server->tcpStatus != CifsNeedReconnect) { - spin_unlock(&server->srv_lock); - break; - } - spin_unlock(&server->srv_lock); - - if (retries && --retries) - continue; + rc = wait_for_server_reconnect(server, smb2_command, tcon->retry); + if (rc) + return rc; - /* - * on "soft" mounts we wait once. Hard mounts keep - * retrying until process is killed or server comes - * back on-line - */ - if (!tcon->retry) { - cifs_dbg(FYI, "gave up waiting on reconnect in smb_init\n"); - return -EHOSTDOWN; - } - retries = server->nr_targets; - } + ses = tcon->ses; spin_lock(&ses->chan_lock); if (!cifs_chan_needs_reconnect(ses, server) && !tcon->need_reconnect) { -- 2.39.2